Then all you need to find are the fixed points of the function $\displaystyle g(y)=f(2y)$. This can sometimes be realised by a simple iteration $\displaystyle y_{n+1}=g(y_n)$ for a suitable starting value $\displaystyle y_0$, but you shouldn't rule out the need for more advanced methods.

Then all you need to find are the fixed points of the function $\displaystyle g(y)=f(2y)$. This can sometimes be realised by a simple iteration $\displaystyle y_{n+1}=g(y_n)$ for a suitable starting value $\displaystyle y_0$, but you shouldn't rule out the need for more advanced methods.

Yes, now you mention it. That is what I started with but for some reason changed it to what I had posted